For commercial and military applications integrated circuits must be fabricated to function properly over a wide temperature range. Further the economics of manufacturing integrated circuits requires that the circuits be designed for proper operation despite parameter variations due to manufacturing operations. Analog integrated circuits in particular often require reference signals for such purposes as regulating power consumption, stabilization of operational amplifiers and biasing of selected circuit elements.
Band gap voltage reference circuits have been used to generate temperature independent voltages, however, these circuits have not been successfully applied to CMOS (complementary metal oxide semiconductor) integrated circuits for generating temperature independent currents.
In view of these problems there exists a need for a reference circuit for generating a reference current which is essentially independent of temperature and processing and can be implemented with CMOS technology.